ethyl 2-amino-1H-pyrrole-3-carboxylate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under an argon atmosphere, 658 mg (2.0 mmol) of N-benzyl-2-bromo-pyridinium bromide (for preparation see: J. Heterocyclic Chem. 28, 1083 (1991)) are introduced into 20 ml of abs. methylene chloride, and 308 mg (2.0 mmol) of 2-amino-pyrrole-3-carboxylic acid ethyl ester [for preparation see: J. Heterocyclic Chem. 23, 1555 (1986)] are added thereto. The reaction mixture is stirred for 2 days with the exclusion of light. Since the reaction is not complete, 232 μl (2 mmol) of 2,6-lutidine and a further 0.20 mmol of 2-amino-pyrrole-3-carboxylic acid ethyl ester are added. After a further 12 hours' stirring, the reaction mixture is concentrated by evaporation and the residue is digested in isopropanol. Filtering, washing with hexane and drying yield the title compound which, according to its 1H-NMR spectrum, still contains approximately 10% N-benzyl-2-bromo-pyridinium bromide; 1H-NMR (300 MHz, DMSO-d6): 11.45 (1H), 8.70 (d, J=7, 1H), 8.38 (t, J=7, 1H), 8.00 (d, J=7, 1H), 7.67 (t, J=7, 1H), 7.42 (m, 3H), 7.14 (d, J=7, 2H), 6.85 (d, J=3, 1H), 6.45 (sb, 2H), 5.91 (s, 2H), 4.13 (q, J=7, 2H), 1.19 (t, J=7, 3H); FAB-MS: (M+H)+ =322. After a further 12 hours' stirring the reaction mixture is concentrated by evaporation Filtering washing with hexane drying

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under an argon atmosphere, 658 mg (2.0 mmol) of N-benzyl-2-bromo-pyridinium bromide (for preparation see: J. Heterocyclic Chem. 28, 1083 (1991)) are introduced into 20 ml of abs. methylene chloride, and 308 mg (2.0 mmol) of 2-amino-pyrrole-3-carboxylic acid ethyl ester [for preparation see: J. Heterocyclic Chem. 23, 1555 (1986)] are added thereto. The reaction mixture is stirred for 2 days with the exclusion of light. Since the reaction is not complete, 232 μl (2 mmol) of 2,6-lutidine and a further 0.20 mmol of 2-amino-pyrrole-3-carboxylic acid ethyl ester are added. After a further 12 hours' stirring, the reaction mixture is concentrated by evaporation and the residue is digested in isopropanol. Filtering, washing with hexane and drying yield the title compound which, according to its 1H-NMR spectrum, still contains approximately 10% N-benzyl-2-bromo-pyridinium bromide; 1H-NMR (300 MHz, DMSO-d6): 11.45 (1H), 8.70 (d, J=7, 1H), 8.38 (t, J=7, 1H), 8.00 (d, J=7, 1H), 7.67 (t, J=7, 1H), 7.42 (m, 3H), 7.14 (d, J=7, 2H), 6.85 (d, J=3, 1H), 6.45 (sb, 2H), 5.91 (s, 2H), 4.13 (q, J=7, 2H), 1.19 (t, J=7, 3H); FAB-MS: (M+H)+ =322. After a further 12 hours' stirring the reaction mixture is concentrated by evaporation Filtering washing with hexane drying

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under an argon atmosphere, 658 mg (2.0 mmol) of N-benzyl-2-bromo-pyridinium bromide (for preparation see: J. Heterocyclic Chem. 28, 1083 (1991)) are introduced into 20 ml of abs. methylene chloride, and 308 mg (2.0 mmol) of 2-amino-pyrrole-3-carboxylic acid ethyl ester [for preparation see: J. Heterocyclic Chem. 23, 1555 (1986)] are added thereto. The reaction mixture is stirred for 2 days with the exclusion of light. Since the reaction is not complete, 232 μl (2 mmol) of 2,6-lutidine and a further 0.20 mmol of 2-amino-pyrrole-3-carboxylic acid ethyl ester are added. After a further 12 hours' stirring, the reaction mixture is concentrated by evaporation and the residue is digested in isopropanol. Filtering, washing with hexane and drying yield the title compound which, according to its 1H-NMR spectrum, still contains approximately 10% N-benzyl-2-bromo-pyridinium bromide; 1H-NMR (300 MHz, DMSO-d6): 11.45 (1H), 8.70 (d, J=7, 1H), 8.38 (t, J=7, 1H), 8.00 (d, J=7, 1H), 7.67 (t, J=7, 1H), 7.42 (m, 3H), 7.14 (d, J=7, 2H), 6.85 (d, J=3, 1H), 6.45 (sb, 2H), 5.91 (s, 2H), 4.13 (q, J=7, 2H), 1.19 (t, J=7, 3H); FAB-MS: (M+H)+ =322. After a further 12 hours' stirring the reaction mixture is concentrated by evaporation Filtering washing with hexane drying

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Compound 1 (0.68 g, 4.41 mmol) was dissolved in DMF (5 mL). NaH (60% in mineral oil, 0.19 g, 4.7 mmol) was added at room temperature affording rapid gas evolution. The reaction stirred for 0.5 h upon which 3-methyl-1-phenyl-but-2-en-1-one (0.50 g, 3.15 mmol) was added. The reaction stirred for 0.5 h upon which EtOH (5 mL) and NaBH4 (1.19 g) were added. The solution was brought to 60° C. for 0.5 h. and then cooled to room temperature. The solution was quenched with water, extracted with Et2O (3 times), dried (Na2SO4) and concentrated. Flash chromatography (10% AcOEt) to give the desired product as a tan solid (0.60 g, 63% yield). MS Calcd.: 298. Found 299 (M+H). affording rapid gas evolution was added were added The solution was quenched with water extracted with Et2O (3 times) dried (Na2SO4) concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Carbamimidoyl-acetic acid ethyl ester (3.357 g, 25.8 mmol) was dissolved in AcOEt (20 mL). Chloroacetaldehyde (50% solution in water, 1.8 mL, 28.7 mmol) was added rapidly at room temperature. The solution stirred for 2 minutes until a precipitant formed. The solution was then brought to 65° C. for 0.5 h. The reaction mixture was then cooled and flash chromatographed with AcOEt. Product containing fractions were concentrated to give the desired material as a green solid. 0.68 g obtained, 31% yield. 1H NMR (400 MHz, CDCl3) δ 1.32 (t, J=7.2 Hz, 3H), 4.24 (q, J=7.0 Hz, 2H), 5.08 (brs, 2H), 6.10-6.13 (m, 1H), 6.25 (t, J=3.12, 1 Hz), 8.60 (brs, 1H); MS Calcd.: 154. Found 155 (M+H). The solution was then brought to 65° C. for 0.5 h The reaction mixture was then cooled flash chromatographed with AcOEt Product containing fractions were concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Compound 1 (0.68 g, 4.41 mmol) was dissolved in DMF (5 mL). NaH (60% in mineral oil, 0.19 g, 4.7 mmol) was added at room temperature affording rapid gas evolution. The reaction stirred for 0.5 h upon which 3-methyl-1-phenyl-but-2-en-1-one (0.50 g, 3.15 mmol) was added. The reaction stirred for 0.5 h upon which EtOH (5 mL) and NaBH4 (1.19 g) were added. The solution was brought to 60° C. for 0.5 h. and then cooled to room temperature. The solution was quenched with water, extracted with Et2O (3 times), dried (Na2SO4) and concentrated. Flash chromatography (10% AcOEt) to give the desired product as a tan solid (0.60 g, 63% yield). MS Calcd.: 298. Found 299 (M+H). affording rapid gas evolution was added were added The solution was quenched with water extracted with Et2O (3 times) dried (Na2SO4) concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Carbamimidoyl-acetic acid ethyl ester (3.357 g, 25.8 mmol) was dissolved in AcOEt (20 mL). Chloroacetaldehyde (50% solution in water, 1.8 mL, 28.7 mmol) was added rapidly at room temperature. The solution stirred for 2 minutes until a precipitant formed. The solution was then brought to 65° C. for 0.5 h. The reaction mixture was then cooled and flash chromatographed with AcOEt. Product containing fractions were concentrated to give the desired material as a green solid. 0.68 g obtained, 31% yield. 1H NMR (400 MHz, CDCl3) δ 1.32 (t, J=7.2 Hz, 3H), 4.24 (q, J=7.0 Hz, 2H), 5.08 (brs, 2H), 6.10-6.13 (m, 1H), 6.25 (t, J=3.12, 1 Hz), 8.60 (brs, 1H); MS Calcd.: 154. Found 155 (M+H). The solution was then brought to 65° C. for 0.5 h The reaction mixture was then cooled flash chromatographed with AcOEt Product containing fractions were concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Compound 1 (0.68 g, 4.41 mmol) was dissolved in DMF (5 mL). NaH (60% in mineral oil, 0.19 g, 4.7 mmol) was added at room temperature affording rapid gas evolution. The reaction stirred for 0.5 h upon which 3-methyl-1-phenyl-but-2-en-1-one (0.50 g, 3.15 mmol) was added. The reaction stirred for 0.5 h upon which EtOH (5 mL) and NaBH4 (1.19 g) were added. The solution was brought to 60° C. for 0.5 h. and then cooled to room temperature. The solution was quenched with water, extracted with Et2O (3 times), dried (Na2SO4) and concentrated. Flash chromatography (10% AcOEt) to give the desired product as a tan solid (0.60 g, 63% yield). MS Calcd.: 298. Found 299 (M+H). affording rapid gas evolution was added were added The solution was quenched with water extracted with Et2O (3 times) dried (Na2SO4) concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Carbamimidoyl-acetic acid ethyl ester (3.357 g, 25.8 mmol) was dissolved in AcOEt (20 mL). Chloroacetaldehyde (50% solution in water, 1.8 mL, 28.7 mmol) was added rapidly at room temperature. The solution stirred for 2 minutes until a precipitant formed. The solution was then brought to 65° C. for 0.5 h. The reaction mixture was then cooled and flash chromatographed with AcOEt. Product containing fractions were concentrated to give the desired material as a green solid. 0.68 g obtained, 31% yield. 1H NMR (400 MHz, CDCl3) δ 1.32 (t, J=7.2 Hz, 3H), 4.24 (q, J=7.0 Hz, 2H), 5.08 (brs, 2H), 6.10-6.13 (m, 1H), 6.25 (t, J=3.12, 1 Hz), 8.60 (brs, 1H); MS Calcd.: 154. Found 155 (M+H). The solution was then brought to 65° C. for 0.5 h The reaction mixture was then cooled flash chromatographed with AcOEt Product containing fractions were concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under an argon atmosphere, 658 mg (2.0 mmol) of N-benzyl-2-bromo-pyridinium bromide (for preparation see: J. Heterocyclic Chem. 28, 1083 (1991)) are introduced into 20 ml of abs. methylene chloride, and 308 mg (2.0 mmol) of 2-amino-pyrrole-3-carboxylic acid ethyl ester [for preparation see: J. Heterocyclic Chem. 23, 1555 (1986)] are added thereto. The reaction mixture is stirred for 2 days with the exclusion of light. Since the reaction is not complete, 232 μl (2 mmol) of 2,6-lutidine and a further 0.20 mmol of 2-amino-pyrrole-3-carboxylic acid ethyl ester are added. After a further 12 hours' stirring, the reaction mixture is concentrated by evaporation and the residue is digested in isopropanol. Filtering, washing with hexane and drying yield the title compound which, according to its 1H-NMR spectrum, still contains approximately 10% N-benzyl-2-bromo-pyridinium bromide; 1H-NMR (300 MHz, DMSO-d6): 11.45 (1H), 8.70 (d, J=7, 1H), 8.38 (t, J=7, 1H), 8.00 (d, J=7, 1H), 7.67 (t, J=7, 1H), 7.42 (m, 3H), 7.14 (d, J=7, 2H), 6.85 (d, J=3, 1H), 6.45 (sb, 2H), 5.91 (s, 2H), 4.13 (q, J=7, 2H), 1.19 (t, J=7, 3H); FAB-MS: (M+H)+ =322. After a further 12 hours' stirring the reaction mixture is concentrated by evaporation Filtering washing with hexane drying

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Compound 1 (0.68 g, 4.41 mmol) was dissolved in DMF (5 mL). NaH (60% in mineral oil, 0.19 g, 4.7 mmol) was added at room temperature affording rapid gas evolution. The reaction stirred for 0.5 h upon which 3-methyl-1-phenyl-but-2-en-1-one (0.50 g, 3.15 mmol) was added. The reaction stirred for 0.5 h upon which EtOH (5 mL) and NaBH4 (1.19 g) were added. The solution was brought to 60° C. for 0.5 h. and then cooled to room temperature. The solution was quenched with water, extracted with Et2O (3 times), dried (Na2SO4) and concentrated. Flash chromatography (10% AcOEt) to give the desired product as a tan solid (0.60 g, 63% yield). MS Calcd.: 298. Found 299 (M+H). affording rapid gas evolution was added were added The solution was quenched with water extracted with Et2O (3 times) dried (Na2SO4) concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Carbamimidoyl-acetic acid ethyl ester (3.357 g, 25.8 mmol) was dissolved in AcOEt (20 mL). Chloroacetaldehyde (50% solution in water, 1.8 mL, 28.7 mmol) was added rapidly at room temperature. The solution stirred for 2 minutes until a precipitant formed. The solution was then brought to 65° C. for 0.5 h. The reaction mixture was then cooled and flash chromatographed with AcOEt. Product containing fractions were concentrated to give the desired material as a green solid. 0.68 g obtained, 31% yield. 1H NMR (400 MHz, CDCl3) δ 1.32 (t, J=7.2 Hz, 3H), 4.24 (q, J=7.0 Hz, 2H), 5.08 (brs, 2H), 6.10-6.13 (m, 1H), 6.25 (t, J=3.12, 1 Hz), 8.60 (brs, 1H); MS Calcd.: 154. Found 155 (M+H). The solution was then brought to 65° C. for 0.5 h The reaction mixture was then cooled flash chromatographed with AcOEt Product containing fractions were concentrated